Lifting jack



' Sept. 19, 1939.

E. GRASS'MANN LIFTING JACK Filed Jan. 19, 19:59

2 Sheets-Sheet l Sept. 19, 19 39. '5. GRASSMANN 2,173,635

LmIN JACK Filed Jan. 19, 1939 2 Sheets-Sheet 2 Patented Sept. re, 1939PATENT OFFICE;

LIFTING JACK Erich Grassmann, Gelsenkirchen, Germany Application January19, 1939, serlagNo. 251,752

In Germany January 18, 1 38 15 Claims. This invention relates to liftingdevices or jacks. The lifting device according to the inventioncomprises a continuous or linked band of metal which can be wound intospiral form, two members, namely a rotor and a stator, disposedconcentrically so as to enclose an annular space therebetween, ahelically ascending guide track for said band in said annular space, aslot in the outer member of said two concentric members through whichsaid band can pass to said guide track, means for engaging said bandwith the inner member of said two concentric members and means forrotating the rotor relatively to the stator. The structural height ofthe device is low and the device is inexpensive to construct, yet it iscapable of being used for raising loads to a height of several metresand is therefore particularly suitable for lifting aircraft, motor cars,machinery, buildings, etc. When collapsed, the device occupies only asmall space and is therefore particularly adapted for use in militarywork as by the engineering corps. It can be used as a pressure device oras a supporting device or lifting 'deviceand as a' conduit for gases andliquids which can be easily made tight in places where rigid pipescannot be employed. The metal or linked band can be provided with one ormore rows of projecting pins and perforations along its edges, in such away that, when it is formed into a tube, the projecting pins-in oneconvolution of the helix engage in the perforations of the adjacentconvolution, so that the helical convolutions are connected together sothat they can resist pressure without bending; The stator and rotor canbe interchanged as desired, depending upon whether the tube is to rotatewhile being formed or whether the tube is to be formed without rotating.a

in the centre of a rotatable cylindrical casing, which contains the bandwound in the form of a spiral. It is also possible to separate the'09sing which contains the band and the driving means from one anotherif an eccentric arrangement of the head ofthe lifting device is desired.

The casing which contains the band is preferably mounted on rollers orballs in order to reduce friction when the band is'being extended intotubular form. The helical guide track for the band can consist ,of or beprovided with rollers.

In order to form the band into a. cylindrical tube of which theindividual convolutions are of conical form and engage one withinanother, so as to project one above another with overlapping It isadvantageous to fit the rotor and stator edges, the edge of the metalband may be curved. Then the radius of the tube formed from the bandremains constant and the tube is ableto support pressure without pinsand perforations being arranged in the edges of the band.

In order to reduce friction on the helically ascending guide track andto avoid damage to I the edges of the band which carry the load, therollers of the helical track' can be connected together by straps and achain constituted by-blocks which arelinked together may be carried bythe rollers. The rollers can be of conical shape, the I conicitydepending on the radius of the helical guide track. The connectingstraps are provided with elongated holes for the purpose of 15increasing the flexibility.

The blocks forming the chain are preferably bevelled or tapered at thejoints in such a way as to be movable in all directions.

In order that the invention may be readily understood and carried intoeffect, a lifting device constructed in accordance with the invention isillustrated by way of example in the-accompanying drawings, in which:

Figure 1 is a vertical section through the base 25 of the liftingdevice,

Figure 1a isa horizontal half section on the lines la-la of Figure 1,

Figure 2 is a vertical section through the guide track showing a roller,the chain of blocks and 30 the steel band,

Figure 3 isan elevation showing the rollers and part of the chain andsteel band,

Figure 3a is a horizontal section through a part of the chain' of blocFigure 4 is a part plan of the rollers,

Figure 5 is a side=view of one of the straps by which the rollers areconnected, I

Figure 6 is a detail view of another form of band, and

Figure '7 is a perspective view. of the device partly broken away.

Referring to the drawings, the box-like casing I carries at its'centrethe cylindrical stator 8 which has longitudinal grooves" 2| in the outer45 surface. Around the stator is mounted on ball bearings 3 acylindrical rotor II in the innersurface of which a helical guide track22 is cut out. Around the rotor H and between ball bearings 4 is mounteda drum a spirally wound metal band 5. (Figure 1.) The rotor H isprovided with, an opening 24 (Fig. 1a) for guiding the band ,to theannular space 26 a which is enclosed between the rotor and stator. Theband isprovidedlatits lower edge with a 5 25 which carries series ofholes 6 and carries at its upper edge a series of pins l (Figure 2). Theedge 30 of the band may be of circular curvature as shown at 29 inFigure 6. Qn the guide track.22, which preferably slopes upwards towardsthe inside (Figs. 1 and 2), are mounted conical rollers In which areconnected together by means of straps H. The straps l2 are provided withelongated eyes 20 (Figure 5) for enabling the chain formed to be movablein all directions. The rollers l2 support an endless chainformed ofblocks 9 which possess guide slots 23 for the edge of the band 5. Inorder that the chain may be movable to allsides the bolt holes l9 at thejoints are of double conical form, as shown in Figure 3a.

The steel band 5 which passes through said slot 24 in the rotor llengages by means of its pins 1 in the grooves 2lin the stator 8. Whenthe rotor H is rotated through the agency of the toothed wheels l3, M byturning the spindle l5, the'band is raised by means of the chain oflocks 9 carried on the guide track 22 and thus formed into acylindricaltube. Rollers 2 (Figure 1a) press the pins 1 in the convolution 21 intothe holes 6 in the convolution 28, so that the cylindrical tube is ableto resist axial pressure. The band carries a head plate ll'l having aturntable l8 for raising objects. The rollers l0 and the blocks 9 bothof which form an endless chain travel round inside the rotor. Thelifting device can be transported by rolling it on its side 3| or it canbe carried.

It will be noted that the construction shown and described will serveadmirably to accomplish the objects stated above. It is to beunderstood, however, that the construction disclosed above is intendedmerely as illustrative of the invention and not as limiting as variousmodifications therein may be made without departing from the inventionas defined by a proper interpretation of the claims which follow.

I claim: i

1. A lifting device comprising a metal band capable of being wound intospiral form, two members disposed concentrically so as to enclose anannular space therebetween, a helically ascending guide track for saidband in said annular space, a slot in the outer of said two concentricmembers through which said band can pass to said guide track, means forengaging said band with the inner of said two concentric mem' bers andmeans for rotating one of said concentric members relatively to theother.

2. A lifting device comprising a metal band capable of being wound intospiral form, two members disposed concentrically so as to enclose anannular space therebetwcen, a helically ascending guide track for saidband formed in the inner surface of the outer of said concentricmembers, a slot in the outer of said concentric members through whichsaid band can pass to' said guide track, grooves in the outer surface ofthe inner of said concentric members, projections on the band forengaging said grooves and means for rotating one of said concentricmembers relatively to the other.

3. A lifting device comprising a metal band capable of being wound intospiral form, two members disposed concentrically so as to enclose anannular space therebetween, a helically ascending guide track for saidband in said annular space, a slot in the outer of said concentricmembers through which said band can pass to said guide track, means forengaging said band with the inner of said concentric members,projections along one edge of said band, holes along the opposite edgeof the band in which said projections on the edge of the adjacentconvolution engage when the band is wound into helical form and meansfor rotating one of said concentric members relatively to the other.

4. A lifting device comprising a metal band capable of being wound intospiral form, a cylindrical stator having grooves in its outer surface, arotor enclosing said stator so as to form an annular space therebetween,a helically ascending guide track for said metal band in the innersurface of said rotor, a slot in said rotor through which said band canpass to said guide track,

projections on said band for engaging said grooves in said stator, andmeans for rotating said rotor relatively to said stator, so as to extendthe band in the form of a tube in said annular space.

5. A lifting device comprising a metal band capable of being wound intospirial form, two members disposed concentrically so as to enclose anannular space therebetween, a helically ascending guide track for saidband in said annular space, rollers on said guide track, a slot in theouter of said two concentric members through which said band can pass tosaid guide track, means for engaging said band with the inner of saidconcentric members and means for rotating one of said concentric membersrelatively to the other.

6. A lifting device comprising a metal band capable of being wound intospiral form, two members disposed concentrically so as to enclose anannular space therebetween, a casing arranged to rotate on bearingsaround said concentric members in which said band is disposed in spiralform, a helically ascending guide track for said band in said annularspace, a slot in the outer of said two concentric members through whichsaid band can pass to said guide track, means for engaging said bandwith the inner of said concentric members and means for rotating one ofsaid concentric members relatively to the other.

7. A lifting device comprising a metal band capable of being wound intospiral form and for said band-in said annular space, a slot in the outerof said two concentric members through which said band can pass to saidguide track, means for engaging said band with the inner of said twoconcentric members and means for rotating one of said concentric membersrelatively to the other.

8. A lifting device comprising a metal band capable of being wound intospirial form, two members disposed concentrically so as to enclose anannular space therebetween, a helically ascending guide track for saidband in said annular space, rollers on said guide track, strapsconnecting said rollers so as to form an endless chain, a. slot in theouter of said two concentric members through which said band can pass tosaid rollers, means for engaging said band with the inner of said twoconcentric members and means for rotating one of said concentric membersrelatively to the other.

9. A lifting device comprising a metal band capable of'being wound intospiral form, two members disposed concentricallyso as to enclose anannular space therebetween, a helically ascending guide track for saidbandin said annua,17a,ees

lar space, rollers on said guide track, straps connecting said rollersto form an endless chain,

blocks linked together to form an endless chain carried by said rollersfor supporting said band, a slot in the outer of said two concentricmembers through which said band can pass to said blocks, means forengaging said band with the inner of said two concentric members andmeans for rotating one of said concentric members rela tively to theother.

10. A lifting device as claimed in Claim 9, wherein said blocks areprovided with grooves for receiving the edge of the metal band.

11. A lifting device as claimed in Claim 5, wherein said rollers areconical and the guide track on which they are supported slopes upinwardly towards the centre.

12. A lifting device comprising a metal band capable of being wound intospiral form, a cylindrical stator having vertical grooves in its outersurface, a rotor enclosing said stator so as to form an annular spacetherebetween, a casing mounted to rotate around said rotor and stator inwhich said band isspirally wound, a helically ascending guide track forsaid metal band in the inner surface of said rotor, rollers on saidguide track, a slot in said rotor through which said band can pass tosaid guide track, projections on said band for engaging said grooves insaid stator, projections along one edge of the band, holes along theopposite edge of the band in which the projections of the adjacentconvolutions engage when the band is wound into helical form, and

means for rotating said rotor relatively to said stator.

13. A lifting device comprising a metal band capable of being wound intospiral form, a cylindrical stator having grooves in its outer surface, arotor enclosing said stator so as to form an annular space therebetween,a helically ascending guide track for said metal band in the innersurface of said rot'or, a slot in said rotor through which said band canpass to said guide track, projections on said band for engaging saidgrooves in said stator, projections along one edge of the band, holesalong the opposite edge of the band in which the projections of theadjacent convolutions engage when the band is wound into helical formand means for rotating said rotor relatively to said stator.

14. A lifting device comprising a metal band having a curved edge andcapable of being wound into spiral form, a cylindrical stator havinggrooves in its outer surface, a rotor enclosing said stator so as toform an annular space therebetween, a helically ascending guide trackfor said metal band in the inner surface of said rotor, a slot in saidrotor through which said band can pass to said'guide track, projectionson said band for engaging said grooves in said stator, and means forrotating said rotor relatively to said stator.

15. A lifting device as claimed in Claim 1', wherein the band iscomposed of links.

ERICH GRASSMANN.

